Turning arrangement for sheets superimposed in a stack and having differing front and rear sides

ABSTRACT

A sheet reversing or turning arrangement for sheets which are superimposed in a stack and having differing front and rear sides, and which are adapted to be pulled off sideways in a sequential manner through the intermediary of gripper elements engaging the leading edge of the respective uppermost sheet of the stack. A second set of gripper elements is provided along the rear edge of the stack, which is movable from a first operative position above the rear edge of the stack into a second operative position rearwardly of the rear edge while carrying along the uppermost sheet through engagement with the rear edge thereof, and which is then movable from the second position back into the first position without the sheet, and including a third set of gripper elements movable from a first operative position rearwardly of the rear edge of the stack in a trajectory towards a second operative position above the front edge of the stack while carrying along the sheet received from the second set of gripper elements and engaged along the rear edge thereof, and which is then movable back into its first operative position without the sheet.

United States Paten 1 Vits [ 1 Oct. 21, 1975 TURNING ARRANGEMENT FOR SHEETS SUPERIMPOSED IN A STACK AND HAVING DIFFERING FRONT AND REAR SIDES [75] Inventor: Hilmar Vits, Leichlingen, Germany {73] Assignee: Vits Maschinenbau GmbI-I,

Langenfeld, Germany 22 Filed: May 29,1974

21 Appl. No.: 474,433

[30] Foreign Application Priority Data June 1, 1973 Germany 2328007 [52] US. Cl. 271/91; 270/69;271/65 [51] Int. Cl. B65I-I 3/08 [58] Field of Search 271/90, 91, 92, 93, 94,

, Primary ExaminerEvon C. Blunk Assistant ExaminerBruce H. Stoner, Jr. Attorney, Agent, or Firm-Waters, Schwartz & Nissen [57] ABSTRACT A sheet reversing or turning arrangement for sheets which are superimposed in a stack and having differing front and rear sides, and which are adapted to be pulled off sideways in a sequential manner through the intermediary of gripper elements engaging the leading edge of the respective uppermost sheet of the stack. A second set of gripper elements is provided along the rear edge of the stack, which is movable from a first operative position above the rear edge of the stack into a second operative position rearwardly of the rear edge while carrying along the uppermost sheet through engagement with the rear edge thereof, and which is then movable from the second position back into the first position without the sheet, and including a third set of gripper elements movable from a first operative position rearwardly of the rear edge of the stack in a trajectory towards a second operative position above the front edge of the stack while carrying along the sheet received from the second set of gripper elements and engaged along the rear edge thereof, and which is then movable back into its first operative position without the sheet.

7 Claims, 6 Drawing Figures US. Patent 0a. 21, 1975 Sheet 1 012 3,913,906

US. Patent Oct. 21, 1975 Sheet 2 of2 3,913,906

FIELD OF THE INVENTION The present invention relates-to a.sheet reversing or turning arrangement for sheets. which are superimposed ina stack and having differing front and rear sides, and which are adapted to be pulled'off sideways in a sequential manner through the intermediary of gripper elements engaging the leading edge of the respective uppermost sheet of the stack.

In the manufacture of decorative and commercial laminates, identically-shaped large sheets, and particularly different types of individual sheets, are collected into stacks in that pursuant to a predetermined program, individual sheets are withdrawn or pulled off sideways from a number of adjacent located and different stacks, each of which respectively contain identical sheets, and are collated in superimpposed relationship at a stacking location. If among the sheets which are being collated there are sheets whose front and rear sides are different, then the collation of that kind of sheet must be carried out while'considering the relative position of its front and rear side, so that the sheet is deposited at the stacking location with either its front or rear side upwardly oriented.

SUMMARY OF THE INVENTION the uppermost sheet through engagement with the rear edge thereof, and which isthen movable from the second position backinto the first position without the sheet, and includinga third set of gripper elements movable from a first operative position rearwardly of the rear edge of the stack in a trajectory towards a second operative position above the front edge of the stack while carrying along the sheet received from the second set of gripper elements and engaged along the rear edge thereof, and which is then movable back into its first operative position without the sheet.

By means of the inventive sheet turning arrangement, the sheet which is to be turned over is turned in a type of folding sequence. The preparation for the-turning is thus effected while pulling back of the sheet so as to lay free the leading edge of the therebelow positioned sheet, so that withdrawal of the latter lower positioned sheet canbe carried out during the-turning of the uppermost 'sheet. The folding sequence facilitates the turning to be effected while carefully treating the sheet so as to avoiddamage thereto.

From a constructive viewpoint, the sheet turning arrangernent is quite simple since the individual'elements need not carry out any complex movements.

The inventive reversing arrangement is particularly adapted for utilization jnan arrangement for the collation at a collecting station of identically-shaped,"large and, particularly, differing types of sheets which are collected-from a plurality of dispensing stations as disclosed, for example, in German Patent application No. 2323339.

Suitably, the gripper elements may each consist of in-and-out actuatable suction elements. Such suction elements are, for example, the subject of German Pabeing excessively creased in the region of the fold thereof, in accordance with an embodiment of the invention there may be provided along the center of the stack and extending transversely of the direction of sheet withdrawal, a preferably tubular support element about which the sheet is positioned. In order to prevent a displacement of the turned sheet upon withdrawal of a'therebelow positioned sheet, in addition to the support element there may also be provided a retaining member which exerts an aspirating or suction action on the turned sheet.

Preferably, the first and second set of gripper elements are so connected to each other, whereby the movement of the second set of gripper elements is opposite to the oscillating motion of the first set of gripper elements.

BRIEF DESCRIPTION OF THE DRAWINGS In the following detailed description of an exemplary embodiment of the invention, reference may now be had to'the accompanying drawings, in which FIGS. 1 through 6 in side elevational view schematically illustrate a sheet turning arrangement located above a stack in various sequential operative positions thereof.

DETAILED DESCRIPTION 7 carriage 3 effects an oscillating to-and-fro movement,

whose amplitude corresponds to the spacing between two adjacent located stations. At the reversing location -of the to-and-fro oscillating movement of the transport carriage 3, the latter is adapted to be either raised or lowered. The gripper elements 2 are constructed of rubber-elastic bellows each having a downwardly opening suction cup extending toward the stack 1, and which are connected to a reduced pressure or vacuum conduit 4. Due to the asymmetrical spring elasticity of "the bellows, the bellows of the suction elements 2 tilt to a small extent and raise the leading edge of the sheet to a larger'degree so as to permit blow nozzles 5 which are located along the leading edge of the stack 1 to blow air between the uppermost sheet and the therebelow positioned sheet. The blown air forms an air cushion below the uppermost sheet and assists in the withdrawal of the sheet.

Along the rear side of the stack similar blow nozzles 6 are provided and are directed against the stack. Furthermore, a set of gripper elements 7 is associated with the rear side of the stack, with the gripper elements similarly being formed as suction cups with asymmetrical spring elasticity and which are connected to a reduced pressure or vacuum conduit 8. The suction cups 7 are supported by a carriage 9 which is movable in toand-fro oscillating movement opposite to transport carriage 3, and which may be raised or lowered at the reversing points of its to-and-fro movement. Adjacent the blow nozzle 6 there is located a set of gripper elements 10 in the form of a tube which has a plurality of suction apertures formed therein. These gripper elements 10 may be pivoted along an are through an angle of 180 about a turning axis 11 above stack 1. Approximately in the center above stack 1, and extending transverse to the direction of sheet transportation, there is provided a support element 12 having the form of a tube with a relatively larger diameter. Extending in parallel with, and in the direction of sheet withdrawal ahead of the support element 12 and above the stack 1, there is provided a cabinet-like retaining member 13 having a plurality of suction apertures.

The sheet turning arrangement operates in the following manner:

In the operative position of the arrangement illustrated in FIG. 1, the transport carriage 3, as well as carriage 9 with gripper elements 2, 7 are lowered on the stack 1, and the gripper elements 2, 7 are activated by means of the switched-in reduced pressure or vaccum. Consequently, the bellows of the suction elements 2 are closed off by the evenly turned sheet 14, which lies above the leading edge of stack 1, while the bellows of the suction elements 7 are closed off by sheet so that in both bellows of the gripper elements 2, 7 there can be formed a reduced or suction pressure which tends to slightly incline the suction cups with the sheets which are engaged along the edges thereof. Subsequently, the carriages 3, 9 are raised into the position shown in FIG. 2. From this position, the transport direction 3 is displaced in the direction of the inherent transport movement to an extent so that the sheet 14 which is gripped from its gripper elements 2 is completely withdrawn sideways from the stack 1. The carriage 9 is displaced in the opposite direction for a distance corresponding to a part length of stack 1, so that its gripper elements 7 assume the position shown in FIG. 3. During the pulling off or withdrawal of sheet 14 and sheet 15, air is blown by the blow nozzles 5, 6 between the presently uppermost sheets 14, 15 and the therebelow positioned sheet so as to render easier the withdrawal while preventing the pulling along of the therebelow positioned sheet. The carriage 9 with the gripper elements 7 is then lowered so that the sheet 15 is adapted to be gripped by the gripper elements 10 which are formed of suction elements. This operative position is illustrated in FIG. 4 of the drawing. After the displacement of carriage 3, 9 from the operative position shown in FIG. 1 into the operative positions shown, respectively, in FIGS. 3 and 4, the gripper elements 2, 7 are deactivated. Proceeding from the operative position illustrated in FIG. 4 the sheet 15, through the intermediary of gripper elements 10 of support element 12 which are rotatable about rotational axis 11, is folded about the support element 12 and is then located in the operative position shown in FIG. 5, in which its leading edge closes with the leading edge of the stack 1. In this operative position, the sheet 15 is retained by the retaining member 13, the latter of which exerts a suction affect on the sheet 15, so that the sheet 15 also cannot be displaced when the sheet 14 or another sheet which is gripped by gripper elements 2 has not yet been fully withdrawn or pulled off from stack 1. From. the operative position of FIG. 5, the gripper elements 10 are then moved back after deactivation and returned to their original operative position, which is shown in FIG. 5. Subsequently, by means of carriages 3 and 9, the gripper elements 2, 7 are again conveyed to above, respectively, the leading edge or rear edge of the stack, from which they then are moved into the operative position of FIG. 1.

A sheet need not always be gripped and transported by the gripper elements 2, 7. Thus, through a corresponding control over the actuation and deactivation, and in particular of the gripper elements 2, 7, it may be determined as to when a sheet is to be turned over and sideways withdrawn. If a sheet is to be withdrawn in an unturned mode, this may be carried out in that, during the movement phases of FIGS. 2 and 3, the gripper elements 7 are not activated so as to thereby move empty. If the gripper element 2 is then moved over the sheet, as shown in FIGS. 6 and 1, it engages the uppermost unturned sheet.

While there has been shown what is considered to be the preferred embodiment of the invention, it will be obvious that modifications may be made with come within the scope of the disclosure of the specification.

What is claimed is:

1. Turning arrangement for superimposed stacked sheets having differing from and rear sides, comprising gripper elements adapted to engage the leading edge of the presently uppermost sheet in the stack and for sideways withdrawing of said sheet from the front edge of said stack; a plurality of second gripper elements located in a first operative position above the rear edge of said stack, said second gripper elements adapted to engage the rear edge of a second sheet located immediately below said uppermost sheet and being movable in conjunction with said second sheet to a second operative position rearwardly of the rear edge of said stack and from said second operative position to said first operative position without said sheet; and a plurality of third gripper elements movable from a first operative position rearwardly of the rear edge of said stack in a trajectory towards a second operative position above the front edge of said stack while conveying said second sheet received from said second gripper elements and then movable to the first operative position thereof without said sheet.

2. Turning arrangement as claimed in claim 1, said gripper elements comprising selectively actuatable suction means.

3. Turning arrangement as claimed in claim 1, in their respective second and first operative positions said second gripper elements being located above and said third gripper elements being located below the sheet conveyed from the stack to the rear position.

4. Turning arrangement as claimed in claim 3, said plurality of third gripper elements in the first operative sheet being positioned proximate said tubular support element.

7. Turning arrangement as claimed in claim 1, said plurality of first and second gripper elements having relative movements imparted thereto so that movement of said second gripper elements is in opposition to the to-and-fro movement of said first gripper elements l l= l= 

1. Turning arrangement for superimposed stacked sheets having differing front and rear sides, comprising gripper elements adapted to engage the leading edge of the presently uppermost sheet in the stack and for sideways withdrawing of said sheet from the front edge of said stack; a plurality of second gripper elements located in a first operative position above the rear edge of said stack, said second gripper elements adapted to engage the rear edge of a second sheet located immediately below said uppermost sheet and being movable in conjunction with said second sheet to a second operative position rearwardly of the rear edge of said stack and from said second operative position to said first operative position without said sheet; and a plurality of third gripper elements movable from a first operative position rearwardly of the rear edge of said stack in a trajectory towards a second operative position above the front edge of said stack while conveying said second sheet received from said second gripper elements and then movable to the first operative position thereof without said sheet.
 2. Turning arrangement as claimed in claim 1, said gripper elements comprising selectively actuatable suction means.
 3. Turning arrangement as claimed in claim 1, in their respective second and first operative positions said second gripper elements being located above and said third gripper elements being located below the sheet conveyed from the stack to the rear position.
 4. Turning arrangement as claimed in claim 3, said plurality of third gripper elements in the first operative position thereof being located between the rear edge of said stack and said plurality of second gripper elements in the second operative position of the latter.
 5. Turning arrangement as claimed in claim 1, comprising a generally tubular support element extending centrally above said stack adapted to be encompassed by said turned uppermost sheet.
 6. Turning arrangement as claimed in claim 5, comprising suction retaining means acting on said turned sheet being positioned proximate said tubular support element.
 7. Turning arrangement as claimed in claim 1, said plurality of first and second gripper elements having relative movements imparted thereto so that mOvement of said second gripper elements is in opposition to the to-and-fro movement of said first gripper elements. 